Dispersed irrigation configuration for catheter tip design

ABSTRACT

This disclosure is directed to a diagnostic catheter having an improved irrigation system for reducing thrombus formation. The catheter may have an irrigated electrode assembly with a plurality of spines, each with a plurality of irrigation ports to flush the device and reduce the risk of thrombus formation.

FIELD OF THE PRESENT DISCLOSURE

This invention relates to diagnostic catheters, in particular,electrophysiological (EP) catheters for mapping and/or ablation in theheart. More particularly, this disclosure relates to irrigated cathetersthat have an improved irrigation catheter tip design.

BACKGROUND

Electrophysiology catheters are commonly-used for mapping electricalactivity in the heart. Various electrode designs are known for differentpurposes. In particular, catheters having basket-shaped electrode arraysare known and described, for example, in U.S. Pat. Nos. 5,772,590,6,748,255 and 6,973,340, the entire disclosures of each of which areincorporated herein by reference.

Basket catheters typically have an elongated catheter body and abasket-shaped electrode assembly mounted at the distal end of thecatheter body. The basket assembly has proximal and distal ends andcomprises a plurality of spines connected at their proximal and distalends. Each spine comprises at least one electrode. The basket assemblyhas an expanded arrangement wherein the spines bow radially outwardlyand a collapsed arrangement wherein the spines are arranged generallyalong the longitudinal axis of the catheter body.

It has been observed that there is an increased risk of thrombusformation when using catheters that change shape from a linear deliveryconfiguration to an expanded diagnostic configuration. Thrombusformation may occur around device features that slow down the flow ofblood. Catheters typically release irrigation fluid to reduce this risk.However, diagnostic catheters include only a single irrigation lumenthat has a port at the distal end of the catheter. Oftentimes, thissingle port is not sufficient to flush the entire device from theproximal end to the distal end which may lead to thrombus formation.Therefore, it is desirable to design a catheter that has an improvedirrigation system to reduce or eliminate the risk of thrombus formation.The techniques of this disclosure satisfy this and other needs asdescribed in the following materials.

SUMMARY

The present disclosure is directed to a catheter, the catheter includesan elongated catheter body having proximal and distal ends and at leastone irrigation lumen therethrough and an irrigated electrode assembly atthe distal end of the catheter body, the irrigated electrode assemblycomprising a plurality of spines having proximal and distal ends, theplurality of spines being connected at their proximal ends, each spinehaving a plurality of electrodes, and at least one irrigation portadjacent a distal end of the elongated catheter body in fluidcommunication with the at least one irrigation lumen.

In one aspect, each spine may have a plurality of irrigation ports influid communication with the spine lumen.

In one aspect, at least one of the irrigation ports may be a dedicatedirrigation port. Alternatively or in addition, at least one of theirrigation ports may be integrated with an electrode having a pluralityof perforations. Accordingly, a combination of dedicated irrigationports and integrated irrigation ports may be employed.

In one aspect, the irrigation ports may be distributed evenly across theirrigated electrode assembly.

In one aspect, the plurality of spines are connected at their distalends to form an irrigated basket-shaped electrode assembly having anexpanded arrangement wherein the spines bow radially outwardly and acollapsed arrangement wherein the plurality spines are arrangedgenerally along a longitudinal axis of the catheter body.

In one aspect, the at least one irrigation lumen comprises a secondirrigation lumen having a second irrigation port adjacent the distalends of the plurality of spines and in fluid communication with the atleast one irrigation lumen.

In one aspect, the catheter further comprises an expander havingproximal and distal ends and a central lumen in fluid communication withthe at least one irrigation port adjacent the proximal end of theplurality of spines and the second irrigation port adjacent the distalends of the plurality of spines, the expander slidably disposed withinthe at least one irrigation lumen and aligned with the longitudinal axisof the catheter body, wherein the plurality of spines are attached attheir distal ends to the expander and each spine includes a spine lumenand a least one spine irrigation port in fluid communication with thespine lumen, each spine lumen being in fluid communication with the atleast one irrigation lumen.

In one aspect, the catheter comprises an elongated catheter body havingproximal and distal ends and at least one irrigation lumen therethroughand an irrigated electrode assembly at the distal end of the catheterbody, the irrigated electrode assembly comprising a plurality of spinesconnected at their proximal ends, each spine comprising a plurality ofelectrodes, a spine lumen and at least one irrigation port in fluidcommunication with the spine lumen, wherein each spine lumen is in fluidcommunication with the irrigation lumen.

This disclosure also includes a method for treatment that may involveproviding a catheter comprising an elongated catheter body havingproximal and distal ends and at least one irrigation lumen therethroughand an irrigated electrode assembly at the distal end of the catheterbody, the irrigated electrode assembly comprising a plurality of spineshaving proximal and distal ends, the plurality of spines being connectedat their proximal ends, each spine having a plurality of electrodes, andat least one irrigation port adjacent a proximal end of the irrigatedelectrode assembly in fluid communication with the at least oneirrigation lumen, advancing the distal end of the catheter with theirrigated electrode assembly to a desired region within a patient,positioning the irrigated electrode assembly such that at least oneelectrode is in contact with tissue, and supplying irrigation fluid tothe irrigation lumen so that the irrigation fluid perfuses through theat least one irrigation port.

In one aspect, the method for treatment may involve providing a cathetercomprising an elongated catheter body having proximal and distal endsand at least one irrigation lumen therethrough and an irrigatedelectrode assembly at the distal end of the catheter body, the irrigatedelectrode assembly comprising a plurality of spines connected at theirproximal ends, each spine comprising a plurality of electrodes, a spinelumen and at least one irrigation port in fluid communication with thespine lumen, wherein each spine lumen is in fluid communication with theirrigation lumen, advancing the distal end of the catheter with theirrigated electrode assembly to a desired region within a patient,positioning the irrigated electrode assembly such that at least oneelectrode is in contact with tissue and supplying irrigation fluid tothe irrigation lumen so that the irrigation fluid perfuses through theirrigation ports.

In one aspect, electrical signals may be received from the at least oneelectrode in contact with tissue.

In one aspect, radio frequency energy may be delivered to the at leastone electrode in contact with tissue to form a lesion.

In one aspect, the desired region may be an atrium or a ventricle of theheart.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages will become apparent from the followingand more particular description of the preferred embodiments of thedisclosure, as illustrated in the accompanying drawings, and in whichlike referenced characters generally refer to the same parts or elementsthroughout the views, and in which:

FIG. 1 is a top plan view of a catheter of the present invention,according to one embodiment.

FIG. 2 is a schematic view of the irrigated basket-shaped electrodeassembly of FIG. 1 deployed in the left atrium.

FIG. 3 is a schematic view of an irrigated basket-shaped electrodeassembly, according to one embodiment.

FIG. 4 is a schematic view of one spine of the irrigated basket-shapedelectrode assembly of FIG. 3.

FIG. 5 is a schematic view of another irrigated basket-shaped electrodeassembly, according to one embodiment.

FIG. 6A is a top view of a cabling of a spine of a basket-shapedelectrode assembly with part(s) broken away, according to oneembodiment.

FIG. 6B is an end cross-sectional view of the cabling of FIG. 6A.

FIG. 6C is a side view of the cabling of FIG. 6A, with part(s) brokenaway.

FIG. 7 is a schematic view of another configuration of an irrigatedelectrode assembly, according to one embodiment.

FIG. 8 is a schematic view of the irrigated electrode assembly of FIG. 7deployed in the left atrium.

FIG. 9 is a detail view of a spine of an irrigated electrode assembly,according to one embodiment.

FIG. 10 is a schematic illustration of an invasive medical procedureusing an irrigated basket-shaped electrode assembly, according to oneembodiment.

DETAILED DESCRIPTION

At the outset, it is to be understood that this disclosure is notlimited to particularly exemplified materials, architectures, routines,methods or structures as such may vary. Thus, although a number of suchoptions, similar or equivalent to those described herein, can be used inthe practice or embodiments of this disclosure, the preferred materialsand methods are described herein.

It is also to be understood that the terminology used herein is for thepurpose of describing particular embodiments of this disclosure only andis not intended to be limiting.

The detailed description set forth below in connection with the appendeddrawings is intended as a description of exemplary embodiments of thepresent disclosure and is not intended to represent the only exemplaryembodiments in which the present disclosure can be practiced. The term“exemplary” used throughout this description means “serving as anexample, instance, or illustration,” and should not necessarily beconstrued as preferred or advantageous over other exemplary embodiments.The detailed description includes specific details for the purpose ofproviding a thorough understanding of the exemplary embodiments of thespecification. It will be apparent to those skilled in the art that theexemplary embodiments of the specification may be practiced withoutthese specific details. In some instances, well known structures anddevices are shown in block diagram form in order to avoid obscuring thenovelty of the exemplary embodiments presented herein.

For purposes of convenience and clarity only, directional terms, such astop, bottom, left, right, up, down, over, above, below, beneath, rear,back, and front, may be used with respect to the accompanying drawings.These and similar directional terms should not be construed to limit thescope of the disclosure in any manner.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one having ordinaryskill in the art to which the disclosure pertains.

Finally, as used in this specification and the appended claims, thesingular forms “a, “an” and “the” include plural referents unless thecontent clearly dictates otherwise.

Certain types of electrical activity within a heart chamber are notcyclical. Examples include arterial flutter or arterial fibrillation,and ventricular tachycardia originating in scars in the wall of theventricle that have resulted from infarcts. Such electrical activity israndom from beat to beat. To analyze or ‘map’ this type of electricalactivity, it is desirable to obtain the ‘picture’ as quickly aspossible, such as within one heartbeat. Typically, a basket-shapedelectrode assembly having a high electrode density may be used toaccurately map this electrical activity.

As discussed above, there is an increased risk of thrombus formationwhen using a catheter that has features that slow down blood flow.Features that slow down blood flow include, for example, surfacestructures that transition from a flat surface to a concave surface,puller wires, and those features that narrow the blood flow channel.Blood flow may also be reduced where a small gap is formed between twoparts of a diagnostic device. It is these types of catheters that willbenefit from an improved irrigation system. Consequently, the cathetersdiscussed below include a plurality of irrigation ports to strategicallysupply irrigation fluid around such structures in order to eliminatethrombus formation.

Referring now to FIG. 1, catheter 10 comprises an elongated catheterbody 12 having proximal and distal ends and a control handle 14 at theproximal end of the catheter body, with a basket-shaped electrodeassembly 16 having a plurality of spines 18, each carrying multipleelectrodes 20, mounted at the distal end of the catheter body 12. Thecatheter body 12 comprises an elongated tubular construction having asingle, axial or central lumen (not shown), but can optionally havemultiple lumens if desired. To enable accurate mapping of electricalsignals, for example to detect most or substantially all of theelectrical function of the right or left atrium in as little as a singleheartbeat, it may be desirable to provide an array of electrodes with arelatively high density. As such, the numbers of spines 18 employed maybe six, eight, ten, twelve or any other suitable number. Spines 18 maybe evenly or unevenly distributed radially. Further, each spine 18 mayinclude multiple electrodes 20, such as at least eight, ten, twelve,fourteen and sixteen electrodes per spine. Similarly, the electrodes maybe evenly distributed along the spine or may be skewed proximally,centrally or distally to facilitate analysis of the measured electricalsignals.

The catheter body 12 is flexible, i.e., bendable, but substantiallynon-compressible along its length. The catheter body 12 can be of anysuitable construction and made of any suitable material. Oneconstruction comprises an outer wall made of polyurethane or PEBAX®(polyether block amide). The outer wall comprises an imbedded braidedmesh of stainless steel or the like to increase torsional stiffness ofthe catheter body 12 so that, when the control handle 14 is rotated, thedistal end of the catheter body will rotate in a corresponding manner.The outer diameter of the catheter body 12 is not critical, butgenerally should be as small as possible and may be no more than about10 french depending on the desired application. In one aspect, theoverall diameter of the catheter body 12 may relate to the number ofelectrodes 20 implemented by basket-shaped electrode assembly 16 inorder to accommodate the associated electrical leads. For example, atwelve-spine design with each spine carrying sixteen electrodes for atotal of 192 electrodes, a ten-spine design with each spine carryingsixteen electrodes for a total of 160 electrodes and an eight-spinedesign with each spine carrying sixteen electrodes for a total of 128electrodes may utilize up to a 10.0 french catheter body. Likewise thethickness of the outer wall is not critical, but may be thin enough sothat the central lumen can accommodate a puller wire, lead wires, sensorcables and any other wires, cables or tubes. If desired, the innersurface of the outer wall is lined with a stiffening tube (not shown) toprovide improved torsional stability. An example of a catheter bodyconstruction suitable for use in connection with the present inventionis described and depicted in U.S. Pat. No. 6,064,905, the entiredisclosure of which is incorporated herein by reference.

The basket-shaped electrode assembly 16 may also include an expander 22that is generally coaxial with the catheter body 12 and extends from theproximal end of catheter body 12 through the central lumen and isattached, directly or indirectly, to the distal ends of spines 18. Theexpander 22 is afforded longitudinal movement relative to the catheterbody so that it can move the distal ends of the spines 18 proximally ordistally relative to the catheter body 12 to radially expand andcontract, respectively, the electrode assembly. Since the proximal endsof spines 18 are secured to the catheter body 12, relative movement ofexpander 22 in the proximal direction shortens the distance between thedistal and proximal ends of spines 18, causing them to bow outwards intoan expanded arrangement. The expander 22 comprises a materialsufficiently rigid to achieve this function. Alternatively or inaddition, spines 18 may include a material as described below thatfacilitates assuming the expanded arrangement, such as a shape memorymaterial, so that expander 22 may be omitted or may be used to aid thetransition between the expanded and collapsed arrangements. In anembodiment, the expander 22 may comprise a wire or hypotube formed froma suitable shape memory material, such as a nickel titanium alloy asdescribed below. As will be appreciated, different relative amounts ofmovement of the expander 22 along the longitudinal axis may affect thedegree of bowing, such as to enable the spines 18 to exert greaterpressure on the atrial tissue for better contact between the tissue andthe electrodes on the spines. Thus, a user can change the shape of theelectrode assembly by adjusting the longitudinal extension or withdrawalof the expander.

Referring now to FIGS. 1 and 3, catheter body 12 further comprisesirrigation ports 80 and 82 configured to supply a suitable irrigationfluid, such as heparinized saline, to electrode assembly 16. Irrigationport 80 receives irrigation fluid via irrigation lumen 26. Lumen 26extends from handle 14 and terminates at the distal end of catheter body12. In this embodiment, port 80 supplies irrigation fluid to theproximal end of irrigated electrode assembly 16. At this location, theproximal ends of spines 18 are slightly separated leaving small gapsbetween each pair when the device is deployed. Fluid exiting port 80flushes this area to reduce thrombus formation.

Irrigation port 82 receives irrigation fluid from irrigation lumen 86.In this embodiment, expander 22 includes a central lumen that is influid communication with an irrigation fluid supply in handle 14 and adistal end that terminates at irrigation port 82. Irrigation port 82supplies irrigation fluid to the region surrounding distal cap 24. Atthis location, the plurality of spines 18 are also close together as attheir proximal ends, but each spine has a concave shape adjacent towhere it is attached to distal cap 24. This concave shape may increasethrombus formation. Irrigation fluid from irrigation port 82 flushesthis area to reduce this risk.

As shown in FIG. 2, when the basket-shaped electrode assembly 16 assumesthe expanded configuration, spines 18 bow outwards into contract orcloser proximity with the walls of the chamber in which it has beendeployed, such as the left atrium. Correspondingly, relative movement ofexpander 22 in the distal direction lengthens the distance between thedistal and proximal ends of spines 18, causing them to assume agenerally linear configuration in line with the catheter body 12 tominimize their outer diameter for insertion within and withdrawal fromthe patient.

In one aspect, an electrophysiologist may introduce a guiding sheath,guidewire and dilator into the patient, as is generally known in theart. As an example, a suitable guiding sheath for use in connection withthe inventive catheter is a 10 french DiRex™ Guiding Sheath(commercially available from BARD, Murray Hill, N.J.). The guidewire isinserted, the dilator is removed, and the catheter is introduced throughthe guiding sheath whereby the guidewire lumen in the expander permitsthe catheter to pass over the guidewire. In one exemplary procedure asdepicted in FIG. 2, the catheter is first introduced to the right atrium(RA) via the inferior vena cava (IVC), where it passes through theseptum (S) in order to reach the left atrium (LA).

As will be appreciated, the guiding sheath covers the spines 18 of thebasket-shaped electrode assembly 16 in a collapsed position so that theentire catheter can be passed through the patient's vasculature to thedesired location. The expander 22 may be positioned distally of thecatheter body to allow the spines of the assembly to be flattened whilethe assembly is passed through the guiding sheath. Once the distal endof the catheter reaches the desired location, e.g., the left atrium, theguiding sheath is withdrawn to expose the basket-shaped electrodeassembly 16. The expander 22 is drawn proximally or otherwisemanipulated so that the spines 18 flex outwardly between the distal andproximal junctions. With the basket-shaped electrode assembly 16radially expanded, the ring electrodes 20 contact atrial tissue. Asrecognized by one skilled in the art, the basket-shaped electrodeassembly 16 may be fully or partially expanded, straight or deflected,in a variety of configurations depending on the configuration of theregion of the heart being mapped.

When the basket-shaped electrode assembly 16 is expanded, theelectrophysiologist may map local activation time and/or ablate usingelectrodes 20, which can guide the electrophysiologist in diagnosing andproviding therapy to the patient. The catheter may include one or morereference ring electrodes mounted on the catheter body and/or one ormore reference electrodes may be placed outside the body of the patient.By using the catheter with the multiple electrodes on the basket-shapedelectrode assembly, the electrophysiologist can obtain a true anatomy ofa cavernous region of the heart, including an atrium, allowing a morerapid mapping of the region.

As used herein, the term “basket-shaped” in describing the irrigatedelectrode assembly 16 is not limited to the depicted configuration, butcan include other designs, such as spherical or egg-shaped designs, thatinclude a plurality of expandable arms or spines connected, directly orindirectly, at their proximal and distal ends. In one aspect, theirrigated electrode assembly may include a plurality of expandable armsor spines connected, directly or indirectly, at their proximal ends onlyand not at their distal ends. In one aspect, different sizedbasket-shaped electrode assemblies may be employed depending on thepatient's anatomy to provide a close fit to the area of the patientbeing investigated, such as the right or left atria.

A detailed view of one embodiment of the irrigated basket-shapedelectrode assembly 16 is shown in FIG. 3, featuring a total of twelvespines 18, each carrying sixteen electrodes 20. As noted above, in otherembodiments, different numbers of spines 18 and/or electrodes 20 may beemployed, each of which may be evenly or unevenly distributed asdesired. The distal ends of the spines 18 and the expander 22 may besecured to a distal cap 24. Correspondingly, the proximal ends of thespines 18 may be secured to the distal end of the catheter body 12,while the expander 22 may be routed through lumen 26 of the catheterbody 12 so that the proximal end extends to the control handle 14. Asdescribed above, lumen 26 may also be used to supply a suitableirrigation fluid, to the basket-shaped electrode assembly 16.

Each spine 18 may comprise a flexible wire 28 with a non-conductivecovering 30 on which one or more of the ring electrodes 20 are mounted.In an embodiment, the flexible wires 28 may be formed from a shapememory material to facilitate the transition between expanded andcollapsed arrangements and the non-conductive coverings 30 may eachcomprise a biocompatible plastic tubing, such as polyurethane orpolyimide tubing. For example, nickel-titanium alloys known as nitinolmay be used. At body temperature, nitinol wire is flexible and elasticand, like most metals, nitinol wires deform when subjected to minimalforce and return to their shape in the absence of that force. Nitinolbelongs to a class of materials called Shaped Memory Alloys (SMA) thathave interesting mechanical properties beyond flexibility andelasticity, including shape memory and superelasticity which allownitinol to have a “memorized shape” that is dependent on its temperaturephases. The austenite phase is nitinol's stronger, higher-temperaturephase, with a simple cubic crystalline structure. Superelastic behavioroccurs in this phase (over a 50°-60° C. temperature spread).Correspondingly, the martensite phase is a relatively weaker,lower-temperature phase with a twinned crystalline structure. When anitinol material is in the martensite phase, it is relatively easilydeformed and will remain deformed. However, when heated above itsaustenite transition temperature, the nitinol material will return toits pre-deformed shape, producing the “shape memory” effect. Thetemperature at which nitinol starts to transform to austenite uponheating is referred to as the “As” temperature. The temperature at whichnitinol has finished transforming to austenite upon heating is referredto as the “Af” temperature. Accordingly, the basket-shaped electrodeassembly 16 may have a three dimensional shape that can be easilycollapsed to be fed into a guiding sheath and then readily returned toits expanded shape memory configuration upon delivery to the desiredregion of the patient upon removal of the guiding sheath.

Alternatively, in some embodiments the spines 18 can be designed withoutthe internal flexible wire 28 if a sufficiently rigid nonconductivematerial is used for the non-conductive covering 30 to permit radialexpansion of the basket-shaped electrode assembly 16, so long as thespine has an outer surface that is non-conductive over at least a partof its surface for mounting of the ring electrodes 20. In thisembodiment, each spine may include a separate irrigation lumen and portthat is isolated from any wires or cabling.

A single spine 18 is shown in its expanded, shape memory configurationin FIG. 4. In this embodiment, spine 18 has a middle region 32 having aconvex shape configured to bring electrodes 20 into contact or closeproximity with the wall of the chamber in which it has been positioned.As noted above, the flexible wire 28 has non-conductive covering 30 onwhich the electrodes 20 are positioned. A distal region 34 may exhibit aconcave configuration, positioned generally within a radius of curvatureindicated by the middle region 36. This configuration provides thedistal region 34 with a smooth transition from the flexible wire 28being aligned with the longitudinal axis of catheter body 12 to an apexjoining the middle region 32. Alignment with the longitudinal axisallows for a minimized collapsed diameter, while the concave shapeallows one or more electrodes 20 to be positioned near the apex toprovide sensor coverage for the polar region adjacent the distal cap 24.A proximal region 36 may have a concave configuration, positionedgenerally outside the radius of curvature indicated by the middle region32. Similarly, this configuration provides a smooth transition from themiddle region 32 to the flexible wire again being in alignment with thelongitudinal axis.

Another exemplary embodiment is shown in FIG. 5. In this design,opposing spines 18 are formed by a continuous stretch of flexible wire28 extending through apertures 38 configured as through holes in thegenerally cylindrical distal cap 24. Apertures 38 may be offset in ahelical pattern as shown or in any other suitable manner to accommodateeach loop of flexible wire 28 without interference from each other. Aswill be appreciated, the position of each spine may be stabilized withrespect to its opposing spine since they are formed from a single pieceof wire.

In a further aspect, each spine 18 may include cabling 40 with built-inor embedded lead wires 42 for the electrodes 20 carried by the spine asshown in FIGS. 6A-C. The cabling has a core 44, and a plurality ofgenerally similar wires 42 each covered by an insulating layer 46 thatenables each wire to be formed and to function as a conductor 48. Thecore 44 provides a lumen 50 in which can pass other components such as asupport structure in the form of flexible wire 28 and/or additional leadwire(s), cables, tubing or other components.

In one embodiment, flexible wire 28′ is positioned within lumen 50. Inthis embodiment, at least one of the flexible wires 28′ has beenmodified to include a central irrigation lumen 88 to supply a suitableirrigation fluid to irrigated electrode assembly 16 through at least oneirrigation port 90. As illustrated in FIG. 5, each flexible wire 28′includes an irrigation lumen 88 and at least one irrigation port 90. Inone embodiment, each flexible wire comprises at least one irrigationport 90 located along the flexible wire. As will be described in greaterdetail below, each irrigation port 90 may be a dedicated port or may beintegrated into an electrode, such as by employing a perforatedelectrode, or a combination of these designs may be used.

In one embodiment, the ports are located at an apex. In the same oranother embodiment, the irrigation port 90 is located along flexiblewire 28′ adjacent the distal cap 24. One of skill in the art willrecognize that the number and location of the irrigation ports 90 canvary depending on the configuration of the assembly 16. The irrigationports may be disposed along the length of flexible wire 28′, from theproximal end adjacent the distal end of catheter body 12 to the distalhub 24. In each of these embodiments, the location of the ports is suchas to supply an adequate amount of irrigation fluid to flush the areaand prevent thrombus formation.

In another embodiment, in addition to irrigated electrode assembly 16having irrigation ports 90 disposed on flexible wires 28′, catheter body12 further includes irrigation port 80 at a distal end of the catheter.In another embodiment, irrigation port 82 and associated irrigationlumen 86 may also be included in the catheter design.

One of skill in the art will appreciate that the pressure of theirrigation fluid may change, (i.e.) increase, as the fluid moves from alarger lumen to a smaller lumen within the flexible wire 28′. In oneembodiment, the handle 14 may include a fluid control valve (not shown)to adjust this increased pressure to a more suitable lower pressure andflow rate. The pressure and flow rate may also be regulated using anadjustable pump external to the catheter.

In the following description, generally similar components associatedwith cabling 40 are referred to generically by their identifyingcomponent numeral, and are differentiated from each other, as necessary,by appending a letter A, B, . . . to the numeral. Thus, wire 42C isformed as conductor 48C covered by insulating layer 46C. Whileembodiments of the cabling may be implemented with substantially anyplurality of wires 42 in the cabling, for clarity and simplicity in thefollowing description cabling 40 is assumed to comprise N wires 42A,42B, 42C, . . . 42N, where N equals at least the number of ringelectrodes on each respective spine 18 of the basket-shaped electrodeassembly 16. For purposes of illustration, insulating layers 46 of wires42 have been drawn as having approximately the same dimensions asconductors 48. In practice, the insulating layer is typicallyapproximately one-tenth the diameter of the wire.

The wires 42 are formed over an internal core 44, which is typicallyshaped as a cylindrical tube. The core material is typically selected tobe a thermoplastic elastomer such as a polyether block amide or PEBAX®.Wires 42 are formed on an outer surface 52 of the core 44 by coiling thewires around the tube. In coiling wires 42 on the surface 52, the wiresare arranged so that they contact each other in a “close-packed”configuration. Thus, in the case that core 44 is cylindrical, each wire42 on the outer surface is in the form of a helical coil, configured ina multi-start thread configuration. For example, in the case of the Nwires 42 assumed herein, wires 42 are arranged in an N-start threadconfiguration around core 44.

In contrast to a braid, all helical coils of wires 42 herein have thesame handedness (direction of coiling). Moreover, wires in braidssurrounding a cylinder are interleaved, so are not in the form ofhelices. Because of the non-helical nature of the wires in braids, evenbraid wires with the same handedness do not have a threaded form, letalone a multi-start thread configuration. Furthermore, because of thelack of interleaving in arrangements of wires in embodiments of thecabling, the overall diameter of the cabling produced is less than thatof cabling using a braid, and the reduced diameter is particularlybeneficial when the cabling is used for a catheter.

Once wires 42 have been formed in the multi-start thread configurationdescribed above, the wires are covered with a protective sheath, such asin the form of the non-conductive covering 30 described above. Theprotective sheath material is typically selected to be a thermoplasticelastomer such as for example, 55D PEBAX without additives so that it istransparent. In that regard, the insulating layer 46 of at least one ofwires 42 may be colored differently from the colors of the remainingwires as an aid in identifying and distinguishing the different wires.

The process of coiling wires 42 around the core 44, and then coveringthe wires by the non-conductive covering 30 essentially embeds the wireswithin a wall of cabling 40, the wall comprising the core and thesheath. Embedding the wires within a wall means that the wires are notsubject to mechanical damage when the cabling is used to form acatheter. Mechanical damage is prevalent for small wires, such as 48 AWGwires, if the wires are left loose during assembly of a catheter.

In use as a catheter, an approximately cylindrical volume or lumen 50enclosed by the core 44, that is afforded by embedding smaller wires(such as the 48 AWG wires) in the wall, allows at least a portion of thelumen 50 to be used for other components. It is understood that theplurality of wires 42 shown in the drawings is representative only andthat a suitable cabling provides at least a plurality of wires equal toor greater than the plurality of ring electrodes mounted on each cablingor spine of the assembly. Cabling suitable for use with the presentinvention is described in U.S. application Ser. No. 13/860,921, filedApr. 11, 2013, entitled HIGH DENSITY ELECTRODE STRUCTURE, and U.S.application Ser. No. 14/063,477, filed Oct. 25, 2013, entitledCONNECTION OF ELECTRODES TO WIRES COILED ON A CORE, the entiredisclosures of which have been incorporated above. Each cabling 40 (withembedded lead wires 42) may extend to the control handle 14 for suitableelectrical connection of wires 42, thereby allowing signals measured byelectrodes 20 to be detected.

As noted, each spine 18 and cabling 40 pair carries a plurality of ringelectrodes 20, which may be configured as monopolar or bipolar, as knownin the art. Cabling 40 is schematically shown by a top view in FIG. 6Aand by a side view in FIG. 6C, in which portions of non-conductivecovering 30 have been cut away to expose wires 42 of the cabling 40, aswell as to illustrate the attachment of a ring electrode 20 to thecabling 40. FIG. 6A illustrates cabling 40 prior to attachment ofelectrode 20, while FIG. 6C illustrates the cabling after the ringelectrode has been attached. The ring electrodes 20 may have suitabledimensions to allow them to be slid over sheath 54.

The attachment point for each electrode 20 may be positioned over one ormore of the wires 42, such as wire 42E in the illustrated example. Asection of non-conductive covering 30 above the wire 42E and acorresponding section of insulating layer 46E are removed to provide apassage 54 to conductor 48E. In a disclosed embodiment, conductivecement 56 may be fed into the passage, ring electrode 20 may then beslid into contact with the cement, and finally the electrode may becrimped in place. Alternatively, the ring electrode 20 may be attachedto a specific wire 42 by pulling the wire through non-conductivecovering 30, and resistance welding or soldering the ring electrode tothe wire.

In another embodiment, the irrigated electrode assembly may employ adifferent configuration, such as the multi-spine assembly shown in FIG.7. In this embodiment, the irrigated electrode assembly 16 may include aplurality of expandable spines 18 connected, directly or indirectly, attheir proximal ends only and not at their distal ends. Catheter 10comprises an elongated catheter body 12 having proximal and distal ends,a control handle 14 at the proximal end of the catheter body 12, and anirrigated electrode assembly 16 having a plurality of spines 18, havingfree distal ends and secured at their proximal end to catheter body 12.Catheter body 12 may further comprise irrigation port 80 configured tosupply a suitable irrigation fluid, such as heparinized saline, toelectrode assembly 16. Irrigation port 80 receives irrigation fluid viairrigation lumen 26. Lumen 26 extends from handle 14 and terminates atthe distal end of catheter body 12. In this embodiment, irrigation port80 supplies irrigation fluid to the proximal end of the irrigatedelectrode assembly 16. At this location, the proximal ends of spines 18are slightly separated leaving small gaps between each pair when thedevice is deployed. Fluid exiting port 80 flushes this area to reducethrombus formation.

Although FIG. 7 shows the use of irrigation port 80, it is not requiredfor the operation of the device. In an embodiment, each spine may havemultiple electrodes 20, which may be configured as diagnosticelectrodes, ablation electrodes or both, and at least one irrigationport 90 on at least one spine. As will be described in greater detailbelow, each irrigation port 90 may be a dedicated port or may beintegrated into an electrode, such as by employing a perforatedelectrode, or a combination of these designs may be used. In someembodiments as shown, each spine 18 may have more than one irrigationport 90, and may be provided at any location along the spine. When aspine 18 has multiple irrigation ports 90, they may be arranged in anydistribution along the spine, including evenly or skewed to the proximalor distal ends or to the middle of the spine. In some embodiments,irrigation ports 90 may be distributed evenly across irrigated electrodeassembly 16.

Each spine 18 may have a lumen (not shown in this view for the sake ofclarity) that is in fluid communication with irrigation ports 90.Correspondingly, each spine lumen may be in communication with anirrigation lumen 26 provided in catheter body 12 that may be used tosupply a suitable irrigation fluid, such as heparinized saline, to theirrigated electrode assembly 16. A fitting 29 in the control handle 14may be provided to conduct irrigation fluid from a suitable source orpump into the lumen 26.

Additionally, one or more location sensors 74 may be provided near adistal end of the catheter 10 adjacent the irrigated electrode assembly16 as schematically indicated in FIG. 7. The sensor(s) may each comprisea magnetic-field-responsive coil or a plurality of such coils. Using aplurality of coils enables six-dimensional position and orientationcoordinates to be determined. The sensors may therefore generateelectrical position signals in response to the magnetic fields fromexternal coils to enable a position determination (e.g., the locationand orientation) of the distal end of catheter 10 within the heartcavity to be made.

Exemplary details of aspects of spines 18 are shown in the detail viewof FIG. 9. As shown, spine 18 may include a lumen 88 that is incommunication with irrigation lumen 26. If desired, each spine lumen 88may include a controllable valve so that irrigation fluid may be fed toselected portions of irrigated electrode assembly 16. The irrigationports are also in communication with lumen 88. As noted above, theirrigation ports may be a dedicated port 90 and/or may be integratedinto an electrode 20, having a plurality of perforations 23. Spine 18may comprise a flexible, resilient core 48 with a non-conductivecovering 94 that may also define lumen 88. In an embodiment, core 96 maybe formed from a shape memory material as noted above to facilitate thetransition between expanded and collapsed arrangements. Thenon-conductive covering 94 may comprise a biocompatible plastic tubing,such as polyurethane or polyimide tubing.

To help illustrate use of the electrode assembly 16, FIG. 10 is aschematic depiction of an invasive medical procedure, according to anembodiment of the present invention. Catheter 10, with the basket-shapedelectrode assembly 16 (not shown in this view) at the distal end mayhave a connector 60 at the proximal end for coupling the wires 42 fromtheir respective electrodes 20 (neither shown in this view) to a console62 for recording and analyzing the signals they detect. Anelectrophysiologist 64 may insert the catheter 10 into a patient 66 inorder to acquire electropotential signals from the heart 68 of thepatient. The professional uses the control handle 14 attached to thecatheter in order to perform the insertion. The professional also usescontrol handle 14 to adjust the continuous flow of irrigation fluidthrough irrigated electrode assembly 16 in order to prevent thrombusformation. Console 62 may include a processing unit 70 which analyzesthe received signals, and which may present results of the analysis on adisplay 72 attached to the console. The results are typically in theform of a map, numerical displays, and/or graphs derived from thesignals.

In a further aspect, the processing unit 70 may also receive signalsfrom one or more location sensors 74 provided near a distal end of thecatheter 10 adjacent the basket-shaped electrode assembly 16 asschematically indicated in FIG. 1. The sensor(s) may each comprise amagnetic-field-responsive coil or a plurality of such coils. Using aplurality of coils enables six-dimensional position and orientationcoordinates to be determined. The sensors may therefore generateelectrical position signals in response to the magnetic fields fromexternal coils, thereby enabling processor 70 to determine the position,(e.g., the location and orientation) of the distal end of catheter 10within the heart cavity. The electrophysiologist may then view theposition of the basket-shaped electrode assembly 16 on an image thepatient's heart on the display 72. By way of example, this method ofposition sensing may be implemented using the CARTO™ system, produced byBiosense Webster Inc. (Diamond Bar, Calif.) and is described in detailin U.S. Pat. Nos. 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612and 6,332,089, in PCT Patent Publication WO 96/05768, and in U.S. PatentApplication Publications 2002/0065455 A1, 2003/0120150 A1 and2004/0068178 A1, whose disclosures are all incorporated herein byreference. As will be appreciated, other location sensing techniques mayalso be employed. If desired, at least two location sensors may bepositioned proximally and distally of the basket-shaped electrodeassembly 16. The coordinates of the distal sensor relative to theproximal sensor may be determined and, with other known informationpertaining to the curvature of the spines 18 of the basket-shapedelectrode assembly 16, used to find the positions of each of theelectrodes 20.

The preceding description has been presented with reference to presentlydisclosed embodiments of the invention. Workers skilled in the art andtechnology to which this invention pertains will appreciate thatalterations and changes in the described structure may be practicedwithout meaningfully departing from the principal, spirit and scope ofthis invention. As understood by one of ordinary skill in the art, thedrawings are not necessarily to scale. Accordingly, the foregoingdescription should not be read as pertaining only to the precisestructures described and illustrated in the accompanying drawings, butrather should be read consistent with and as support to the followingclaims which are to have their fullest and fair scope.

What is claimed is:
 1. A catheter comprising: an elongated catheter bodyhaving proximal and distal ends and at least one irrigation lumentherethrough; and an irrigated electrode assembly at the distal end ofthe catheter body, the irrigated electrode assembly comprising aplurality of spines having proximal and distal ends, the plurality ofspines being connected at their proximal ends, each spine having aplurality of electrodes, and at least one irrigation port adjacent adistal end of the elongated catheter body in fluid communication withthe at least one irrigation lumen, each spine including a spine lumenand a flexible wire positioned within the spine lumen, the flexible wireincluding a central irrigation lumen, and each spine including at leastone spine irrigation port in fluid communication with the centralirrigation lumen, each central irrigation lumen being in fluidcommunication with the at least one irrigation lumen.
 2. The catheter ofclaim 1, wherein each spine has a plurality of spine irrigation ports influid communication with the central irrigation lumen.
 3. The catheterof claim 2, wherein at least one of the spine irrigation ports is adedicated spine irrigation port.
 4. The catheter of claim 2, wherein atleast one of the spine irrigation ports is integrated with an electrodehaving a plurality of perforations.
 5. The catheter of claim 2, whereinthe spine irrigation ports comprise a combination of dedicatedirrigation ports and integrated irrigation ports.
 6. The catheter ofclaim 1, wherein the plurality of spines are connected at their distalends to form an irrigated basket-shaped electrode assembly having anexpanded arrangement wherein the spines bow radially outwardly and acollapsed arrangement wherein the plurality spines are arrangedgenerally along a longitudinal axis of the catheter body.
 7. Thecatheter of claim 6, wherein the at least one irrigation lumen comprisesa second irrigation lumen having a second irrigation port adjacent thedistal ends of the plurality of spines and in fluid communication withthe at least one irrigation lumen.
 8. The catheter of claim 7, furthercomprising an expander having proximal and distal ends and a centrallumen in fluid communication with the at least one irrigation portadjacent the proximal end of the plurality of spines and the secondirrigation port adjacent the distal ends of the plurality of spines, theexpander slidably disposed within the at least one irrigation lumen andaligned with the longitudinal axis of the catheter body, wherein theplurality of spines are attached at their distal ends to the expander.9. The catheter of claim 8, wherein each spine includes at least onespine irrigation port in fluid communication with the spine lumen, eachspine lumen being in fluid communication with the at least oneirrigation lumen.
 10. The catheter of claim 9, wherein each spine has aplurality of spine irrigation ports in fluid communication with thespine lumen.
 11. The catheter of claim 10, wherein at least one of thespine irrigation ports is a dedicated spine irrigation port.
 12. Thecatheter of claim 10, wherein at least one of the spine irrigation portsis integrated with an electrode having a plurality of perforations. 13.The catheter of claim 10, wherein the spine irrigation ports comprise acombination of dedicated irrigation ports and integrated irrigationports.
 14. A catheter comprising an elongated catheter body havingproximal and distal ends and at least one irrigation lumen therethroughand an irrigated electrode assembly at the distal end of the catheterbody, the irrigated electrode assembly comprising a plurality of spinesconnected at their proximal ends, each spine comprising a plurality ofelectrodes, a spine lumen and a flexible wire positioned within thespine lumen, the flexible wire including a central irrigation lumen, thespine including at least one irrigation port in fluid communication withthe central irrigation lumen, wherein each central irrigation lumen isin fluid communication with the irrigation lumen.
 15. The catheter ofclaim 14, wherein each spine has a plurality of irrigation ports influid communication with the central irrigation lumen.
 16. The catheterof claim 15, wherein the irrigation ports comprise a combination ofdedicated irrigation ports and integrated irrigation ports.
 17. Thecatheter of claim 15, wherein the irrigation ports are distributedevenly across the irrigated electrode assembly.
 18. The catheter ofclaim 14, wherein at least one of the irrigation ports is a dedicatedirrigation port.
 19. The catheter of claim 14, wherein at least one ofthe irrigation ports is integrated with an electrode having a pluralityof perforations.
 20. The catheter of claim 14, wherein the spines havean expanded arrangement wherein the spines deflect radially outwardlyand a collapsed arrangement wherein the spines are arranged generallyalong a longitudinal axis of the catheter body.
 21. The catheter ofclaim 20, wherein the spines are attached at their distal ends to anexpander, such that the irrigated electrode assembly has the collapsedarrangement when the expander is at a most distal position along thelongitudinal axis relative to the catheter body.
 22. The catheter ofclaim 20, wherein proximal movement of the expander through a range oftravel is associated with conversion of the irrigated electrode assemblyto the expanded arrangement from the collapsed configuration.
 23. Thecatheter of claim 22, wherein the expander is routed through a lumen ofan inner tubular member coaxially disposed within the at least oneirrigation lumen of the elongated catheter body.
 24. A method fortreatment comprising: providing a catheter comprising an elongatedcatheter body having proximal and distal ends and at least oneirrigation lumen therethrough and an irrigated electrode assembly at thedistal end of the catheter body, the irrigated electrode assemblycomprising a plurality of spines having proximal and distal ends, theplurality of spines being connected at their proximal ends, each spinehaving a plurality of electrodes, and at least one irrigation portadjacent a proximal end of the irrigated electrode assembly in fluidcommunication with the at least one irrigation lumen, each spineincluding a spine lumen and a flexible wire positioned within the spinelumen, the flexible wire including a central irrigation lumen, and eachspine further including at least one spine irrigation port in fluidcommunication with the central irrigation lumen, each central irrigationlumen being in fluid communication with the at least one irrigationlumen, advancing the distal end of the catheter with the irrigatedelectrode assembly to a desired region within a patient; positioning theirrigated electrode assembly such that at least one electrode is incontact with tissue; and supplying irrigation fluid to the irrigationlumen so that the irrigation fluid perfuses through the at least oneirrigation port.
 25. The method of claim 24, further comprisingreceiving electrical signals from the at least one electrode in contactwith tissue.
 26. The method of claim 24, further comprising deliveringradio frequency energy to the at least one electrode in contact withtissue to form a lesion.
 27. The method of claim 24, wherein the desiredregion is an atrium or a ventricle.
 28. A method for treatmentcomprising: providing a catheter comprising an elongated catheter bodyhaving proximal and distal ends and at least one irrigation lumentherethrough and an irrigated electrode assembly at the distal end ofthe catheter body, the irrigated electrode assembly comprising aplurality of spines connected at their proximal ends, each spinecomprising a plurality of electrodes, a spine lumen and a flexible wirepositioned within the spine lumen, the flexible wire including a centralirrigation lumen, the spine includes at least one irrigation port influid communication with the central irrigation lumen, wherein eachcentral irrigation lumen is in fluid communication with the irrigationlumen, advancing the distal end of the catheter with the irrigatedelectrode assembly to a desired region within a patient; positioning theirrigated electrode assembly such that at least one electrode is incontact with tissue; and supplying irrigation fluid to the irrigationlumen so that the irrigation fluid perfuses through the irrigationports.
 29. The method of claim 28, further comprising receivingelectrical signals from the at least one electrode in contact withtissue.
 30. The method of claim 28, further comprising delivering radiofrequency energy to the at least one electrode in contact with tissue toform a lesion.
 31. The method of claim 28, wherein the desired region isan atrium or a ventricle.